Automatic size control for honing machines



11, 1964 YOSHITAKA KONDO 3,143,833

AUTOMATIC SIZE CONTROL FOR HONINC MACHINES 2 Sheets-Sheet 1 Filed March 5, 1965 'YOSHITAKA KONDO 3,143,833

AUTOMATIC SIZE CONTROL FOR HONING MACHINES 2 Sheets-Sheet 2 Filed March 5, 1963 INVENTOR. I

United States Patent Ofiice 3,143,833 Patented Aug. 11, 1964 3 43,833 AUTQMATIC SiZE bfiNTRQL FOR HONTNG MACHINES Yoshitaka Kondo, unto-gnn, Shiznoha-hen, Eapan, as-

signor to Fuji Seiki Machine Works, Ltd, Sniznoitaken, Japan, a corporation of Japan Filed Mar. 5, 1963, Ser. No. 262,974 Claims priority, application Japan Get. 9, 1362 7 Claims. (Cl. 51-155) This invention relates to a honing machine, and more particularly, to a new and improved automatic size control for the honing machine.

A honing process under consideration is a machining one for operating on the bores of cylindrical work pieces with a high degree of accuracy and efliciency. In honing the bore of a work by means of a honing apparatus heretofore employed, a honing head or tool provided with a plurality of abrasive stones on the periphery thereof is rotated and reciprocated within the bore of the work to be honed with the stones being expanded in a radial direction to effect the honing action either manually or automatically. It is known that a honing machine equipped with an automatic size control has been available in which the automatic size control is put into action in order to detect the accurate size of the work as soon as it is achieved during the honing operation and shut down the machine immediately, whereby the honing head is returned to its initial position. Several types of the automatic size control have been developed and reduced to actual practice. However, there have been a few disadvantages to be overcome, such as, the presence of impact scars on the work piece, the occurrence of frequent failures due to the incomplete water proofness at the electric sensing means, and the decrease of size accuracy resulting from the deposition of abrasive particles dropped oil from the stone on the sensing means during the honing operation.

In view of the above disadvantages, the present invention contemplates to overcome them and provide a novel and improved automatic size control for a honing ma chine. Briefly stated, the invention is directed to the automatic size control for a honing machine in which when the desired size of the work piece is attained by the honing process, the end period of the expansion of the honing head is detected by the change of the pressure of a working fluid, and the resulting value of the pressure change is converted into an electric signal which functions to shut down the operation of the machine immediately, whereby a high accurate and etiicient honing process is obtained.

Accordingly, it is a principal object of the invention to provide a new and improved automatic size control for a honing machine by which the period when the specified size of a work is reached by the honing operation of a honing head is automatically detected.

It is another object of the invention to provide an improved automatic control for a honing machine in which a cutting oil for use in the honing machine is utilized as a working fluid and a pressure change of the working fluid is also employed.

It is still another object of the invention to provide an automatic size control of an easy operation as well as of a simple construction for a honing machine with a high accuracy and efliciency in which a fluid pressure system is utilized without recourse to a more complicated water repellent means.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

FIG. 1 is a schematic representation of the size control means embodying the invention and incorporated in a honing machine, viewing a vertical and one-spindle machine in front elevation.

FIG. 2 is a similar view to FIG. 1, viewing the honing machine in side elevation.

FIG. 3 is a schematic View of the size control means of the invention utilizing a Bourdon tube to actuate an electric switch in response to fluid pressure.

FIGURE 4 is a schematic view of an alternate embodiment of the electric sensing or detecting means, shown in FIGURE 3 is a Bourdon tube, utilizing a bellows to actuate the electric switch in response to fluid pressure.

FIG. 5 is an enlarged sectional view showing how a plunger in FIG. 3 is before the desired size or dimension of the work is reached.

FIG. 6 is also an enlarged sectional view showing the relative position of the plungers when the desired correct size of the work is attained.

Referring to FIGS. 12 in more detail, the honing machine in general is classified as follows: vertical, horizontal and other types; a single spindle and multi-spindles. It is understood that the automatic size control means of the present invention can be equipped for any type of the honing machine irrespective of the number of spindles. However, for clarity and simplicity of description, I have shown a vertical one-spindle honing machine. Moreover, guides or the like are also omitted in it. It is to be noted that various driving mechanisms necessary for the honing machine, e.g., electric motors and the hydraulic system including honing head expansion are omitted, too, except those directly connected to the size control of the invention.

The automatic size control of this invention consists of three principal means, namely, a size control power source means 1, an electric sensing or detecting means 2 and a mechanical sensing or detecting means 3 as clearly shown in the schematic view of FIG. 3 and a practical application of the invention to a vertical one-spindle honing machine is shown in FIGS. 12.

The size control power source means 1 comprises a tank 4 for storing a cutting oil 5 of a known composition, a motor 6 for driving a pump 7, a pressure control valve 19 for controlling the pressure of the cutting oil 5, a manometer 8, a non-return valve 9 for transmitting the pressure change of the cutting oil to the sensing means in an effective manner, an accumulator 11 for maintaining the cutting oil pressure to be constant, and the connections therefor. It should be emphasized here that the cutting oil 5 is utilized as a working fluid for the control system of the invention. Of course, the use of a cutting oil is necessary for the machining process of the honing machine. However, the same cutting oil as employed in the honing process is utilized as the working fluid for the size control system, which is one of the features of the invention. It is to be noted, however, that the cutting oil supply system necessary for the honing machine is entirely omitted in the accompanying drawings. Thus, the tank 4 for storing the cutting oil 5 is used to store the Working fluid 5 only for the size control.

The electric sensing or detecting means 2 of FIGURE 1 comprises a pressure sensing means shown in FIGURE 3 is a Bourdon tube 13 and in FIGURE 4 as a bellows 13' for sensing or detecting the pressure change of the working fluid 5 and an electric contact means 12 for converting the movement of the pressure sensing means 13 into an electric signal.

The mechanical sensing means 3 comprises a rotatable gage ring 14, a torque control plunger 15 which functions to cause the rotatable gage ring 14 to be rotated only when it is subjected to a predetermined amount of torque,

a size detecting plunger 16 which functions to raise the Epressure of the working fluid being urged when the size igage ring 14 is rotated, a holder 19 for accommodating the gage ring 14 and two plungers, and the connecting pipes therefor.

Next, the operation and function of the honing machine equipped with the automatic size control of the invention will be described in detail hereinbelow. A work W to be honed is placed on a specified position of the honing machine, that is, the position located below the mechanical sensing means 3 as shown in FIG. 1, and it is set into operation. The motor 6. of the power source 1 drives the pump 7 to feed the pressure fluid 5 while a honing head H operates on the work W. As mentioned hereinbefore, the pressure fluid 5 is the same as a cutting oil for the honing process. This working fluid 5 is adjusted to a predetermined amount of pressure, which depends on the material to be honed and the operating condition, being in the range of about 0.5-3 kg. per sq. cm., by the pressure control valve 10. Then, the working fluid 5 fed by, the pump 7 enters the accumulator 11 through the non-return valve 9 and is supplied to the mechanical sensing means 3.

It can be seen that since the working fluid 5 is completely the same as the cutting oil indispensable for the honing operation no trouble will occur if the former supplied to the gage ring 14 of the mechanical sensing means 3 should mix with the latter. The gage ring 14 is rotatably mounted on a holder 19 located above and spaced from the work W, the detail of which mounting including two plungers 15 and 16 is omitted. As the working fluid '5 is discharged from the openings 17 and 18 at all times during a honing cycle, the gage ring 14 is always cleaned by the working fluid 5. It is usual that abrasive particles should be dropped off from the stones during the honing step, and they would deteriorate the size accuracy because of their deposition on the surface of the gage ring 14. However, by the cleaning action of the working fluid 5 mentioned above in accordance with the invention, the deposition of such abrasive particles of the surface of the gage ring 14 is avoided to insure a stable size accuracy.

The working fluid 5 under pressure is delivered to the pressure sensing Bourdon tube 13'0f FIGURE 3 or the bellows 13' of FIGURE 4, the torque control plunger 15, and the size sensing plunger 16 with a predetermined amount of pressure mentioned hereinbefore as clearly shown in FIGS. 5-6. From the openings 17 and 18 the working fluid is discharged to clean the surface of the gage ring 14 as described above.

The honing head H operates on the work W by the simultaneous rotation and reciprocation. In its upward travel, it enters the area of the gage ring 14, but it will not move the ring 14 until the desired dimension or size of the work is attained. As the honing step proceeds, the bore of the work W approaches its size. At the same time the honing head expands in a radial direction to come in contact with the bore of the gage ring 14 to rotate it. However, the gage ring 14 will not be moved by the action of the torque control plunger 15 until a friction reaches a specified amount of torque. Upon reaching the specified dimension or size of the work W by the last finish of the honing cycle, the gage ring 14 will be rotated since the friction exceeds the above specified amount of torque, which results in the urging of the plunger 16 into a holder to close the opening 17 to raise the pressure in the system. The non-return valve 9 is provided to prevent the pressure increase from acting on the pump 7 and the control valve 19 in order not to transmit the pressure in a reverse direction.

The friction and the torque mentioned above depend on the material to be honed and the honing conditions, therefore their actual values are not given. However, these values are easily determined in an actual experiment, so

gas

the automatic size control of the invention will find no difliculty in the reduction to practice.

The plunger 16 is provided with two openings 17 and 18, because the opening 13 prevents the pressure from increasing when the opening 17 is closed, hence the pressure sensing Bourdon tube 13 or the bellows 13' of a small capacity is preferred.

The pressure increase thus obtained acts on the pressure sensing Bourdon tube 13 or the bellows 13' effectively to actuate it, the movement of wmch is transmitted to the electric contact means 12. The electric sensing means 2 of the automatic size control of the invention consists of the pressure sensing Bourdon tube 13 or the bellows 13 for detecting the pressure change of the working fluid 5 and the electric contact means 12 for converting the information resulting from the pressure sensing Bourdon tube 13 or the bellows 13' into an electric signal. As shown in FIGS. 12, the electric sensing means 2 is completely insulated from the place where the working fluid 5 is discharged. Moreover, the electric contact means 12 is arranged to be actuated by the pressure sensing Bourdon tube 13 or the bellows 13' in order to pre vent the working fluid 5 from a direct contact with it, because the working fluid 5 enters the pressure sensing Bourdon tube 13 or the bellows 13. Therefore, no water proof means whatever is required and no trouble resulting from water will happen.

Actuation of the electric contact means 12 closes the electric circuit of the expansion of the honing head of the honing machine to shut down the expansion, thus shut down the operation of the machine. Accordingly, the automatic size control of the invention is suspended and a product of desired size or dimension is obtained.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of parts of the invention without departing from the spirit and scope of the invention, the apparatus being merely a preferred embodiment thereof.

I claim:

1. A honing machine for honing a circular aperture in a workpiece comprising, in part, at least one rotary driven expandable hone, first drive means for rotating said hone, means for mounting a workpiece on said honing machine in a position permitting the honing of an aperture by said expandable hone, an automatic control system for suspending the operation of the honing machine in response to the maximum permissible expansion of said hone in said aperture, said control consisting of; a control fluid, a storage tank for containing said fluid, a presure pump having an inlet and an outlet, sec ond drive means actuating said'pump, means operatively connecting the inlet of said pump to said storage tank to provide a source of control fluid under pressure for said control system, means for maintaining a constant pump outlet pressure, a rotary gauging device mounted adjacent said workpiece and said hone during the honing operation, means resisting rotation of said gauging device, contact means on said gauging device for operatively contacting said expandable hone at the maximum desired expansion of said hone to provide a torque tending to rotate the gauging device against the resisting means, mechanical means for detecting the rotation of said gauging means, means for variably venting said control fluid from a line connected to the outlet of said pump at a point downstream of the pump outle't,'said venting means being operatively connected to said mechanical detectingmeans, means connected to said line for sensing a change in th pressure of said control fluid and converting the pressure change into an intermediate mechanical and then into a final electrical signal whereby the operation of said honing machine may be suspended in response to the electrical signal.

2. n a honing machine as recited in claim 1, said means for detecting the change in fluid pressure in said line and converting said pressure into a final electrical signal being a Bourdon tube and an electro-mechanical switch, said Bourdon tube having its open end connected to said line and a portion of its curved length being movable, by fluid pressure, into the path of an actuator for said electro-mechanical switch.

3. In a honing machine as recited in claim 1, said means for detecting the change in fluid pressure and converting said pressure into a final electrical signal being an expandable bellows and an electro-mechanical switch, said bellows having its open end connected to said line and its opposite end reciprocatable into the path of an actuator for said electromechanical switch.

4. In a honing machine as recited in claim 1, a cutting fluid for said honing process, means for dispensing said cutting fluid into the working path of said hone, said cutting fluid being the same fluid as the control fluid.

5. In a honing machine as recited in claim 1, a one way valve means in said fluid line downstream of said pump outlet and upstream of said variable venting means and the connection for said means for detecting changes in fluid pressure and converting said pressure change into a final electrical signal.

6. In a honing machine as recited in claim 5 wherein said means for resisting the rotation of said gauging device consists of, a radial flange on said gauging device, a hydraulic piston cylinder combination, said cylinder mounted on said honing machine adjacent said gauging device with the outer face of said piston abutting said radial flange, means for connecting the interior of the cylinder to the fluid line downstream of said one way valve.

7. In a honing machine as recited in claim 1, wherein the gauging device consists of a ring, said ring having a concentric circular machined hole, the size of said hole being proportional to the aperture size desired in the workpiece, a pair of radial flanges mounted on said ring, one of said flanges abutting said rotation resisting means and the other of said flanges abutting the variable venting means.

References Cited in the file of this patent UNITED STATES PATENTS 2,284,325 Kline May 26, 1942 2,647,347 Blanchette Aug. 4, 1953 2,866,365 Worthen Dec. 30, 1958 

1. A HONING MACHINE FOR HONING A CIRCULAR APERTURE IN A WORKPIECE COMPRISING, IN PART, AT LEAST ONE ROTARY DRIVEN EXPANDABLE HONE, FIRST DRIVE MEANS FOR ROTATING SAID HONE, MEANS FOR MOUNTING A WORKPIECE ON SAID HONING MACHINE IN A POSITION PERMITTING THE HONING OF AN APERTURE BY SAID EXPANDABLE HONE, AN AUTOMATIC CONTROL SYSTEM FOR SUSPENDING THE OPERATION OF THE HONING MACHINE IN RESPONSE TO THE MAXIMUM PERMISSIBLE EXPANSION OF SAID HONE IN SAID APERTURE, SAID CONTROL CONSISTING OF; A CONTROL FLUID, A STORAGE TANK FOR CONTAINING SAID FLUID, A PRESURE PUMP HAVING AN INLET AND AN OUTLET, SECOND DRIVE MEANS ACTUATING SAID PUMP, MEANS OPERATIVELY CONNECTING THE INLET OF SAID PUMP TO SAID STORAGE TANK TO PROVIDE A SOURCE OF CONTROL FLUID UNDER PRESSURE FOR SAID CONTROL SYSTEM, MEANS FOR MAINTAINING A CONSTANT PUMP OUTLET PRESSURE, A ROTARY GAUGING DEVICE MOUNTED ADJACENT SAID WORKPIECE AND SAID HONE DURING THE HONING OPERATION, MEANS RESISTING ROTATION OF SAID GAUGING DEVICE, CONTACT MEANS ON SAID GAUGING DEVICE FOR OPERATIVELY CONTACTING SAID EXPANDABLE HONE AT THE MAXIMUM DESIRED EXPANSION OF SAID HONE TO PROVIDE A TORQUE TENDING TO ROTATE THE GAUGING DEVICE AGAINST THE RESISTING MEANS, MECHANICAL MEANS FOR DETECTING THE ROTATION OF SAID GAUGING MEANS, MEANS FOR VARIABLY VENTING SAID CONTROL FLUID FROM A LINE CONNECTED TO THE OUTLET OF SAID PUMP AT A POINT DOWNSTREAM OF THE PUMP OUTLET, SAID VENTING MEANS BEING OPERATIVELY CONNECTED TO SAID MECHANICAL DETECTING MEANS, MEANS CONNECTED TO SAID LINE FOR SENSING A CHANGE IN THE PRESSURE OF SAID CONTROL FLUID AND CONVERTING THE PRESSURE CHANGE INTO AN INTERMEDIATE MECHANICAL AND THEN INTO A FINAL ELECTRICAL SIGNAL WHEREBY THE OPERATION OF SAID HONING MACHINE MAY BE SUSPENDED IN RESPONSE TO THE ELECTRICAL SIGNAL. 